Die-punching method



June 18, 1929. w, NORDENDALE 1,718,176

DIE PUNCHING METHOD File Fe 1929 2 Sheets-Sheet 1 June 18, 1929. H, w, NQRDENDALE 1,718,176

DIE PUNCHING METHOD File Feb- 2, 1929 2 Sheets-Sheet 2 AWE P Patented June 18, 1929.

UNITED STATES PATENT 'VOFFICE.

HARRY W. NORDENDALE, OF CHICAGO, ILLINOIS, ASSIG-NOR, BY DIRECT AND ASSIGNMENTS, TO NOBDENDALE MANUFACTURING COMPANY, 01? CHICAGO, ILLI- NOIS, A CORPORATION OF ILLINOIS.

DIE-PUNCHING METHOD.

( Application filed February 2: 1929. Serial No. 337,021.

. This invention relates to a new and improved method of making core laminations used in magnetic circuit apparatus.

In providing the magnetic circuit in cer- 5 tain formsof electrical apparatus, a core is used that is built up of sheet metal laminations, the core consisting ofparallel base members connected by. three parallel leg members so as to form two parallel slots ex-- tending through the core. Each layer or lamination of this core may be formed of a pair of cooperating laminations, comprising an E-shaped member and a single straight bar lamination similar in form to the base of the E and adapted to be positioned across so as to connect the open ends of the legs of the E. The presentinvention relates to a method of forming these i E shaped and-straight laminations from a single continuous strip ofsheet metal so that the laminations will be cut on all sides thereof and be of absolutely uniform shape and size, and substantially all of the metal strip will be utilized. 7 The method also provides- 5"forpunching holes or perforations in the respective ends of the straight laminations and of thebase portions of the E-shaped laminations, through which means may be inserted for holding together the laminations when stacked and assembled to formthe core.

In the accompanying drawings showing a preferred formof machine for practicing the method: Y

one of the presses.

Fig. 2 is a bottom plan view of the upper movable punch member of the press.

F1 3 is a plan view of the lower fixed (lie 40 mem er of the press.

Fig. 4 is a plan view similar to Fig. 3, with the cover plate of the die removed to illustrate the longitudinal guides for the metal strip. 1

Fig. 5 is a detail vertical section, taken substantially on the line 5-5 of Fig.- 4, through one of the yieldable strip guides.

Fig; 6 is a plan viewof the end portion of the C(kltlllllOllS metal strip,- in the condition in which it appears between any two successive strokes of the press after the first complete laminations have been cut.

Figs. 7 and 8 are detail plan views of the Fig. 1 is aside elevation of a portion of form the holes or perforations of the base 12 of each E-shaped lam1nat1on' E-shaped and the straight laminations respectively.

In Fig. 7, the position of the straight lamination of Fig. 8, when assembled with one of the E-shaped laminations to form a core, is indicated in dotted lines.

Referring first to Figs. 1 to 4; of the drawings, only so much ofa die-press or stamping machine is illustrated as is necessary to explain the present invention. It will be understood that the press itself may take a variety of forms and be operatedin any approved manner. As here shown, the press comprises a supporting table or standard 1, carrying a fixed base plate 2 on which the fixed die members are mounted. A vertically reciprocating horizontal carriage or punch-holder 3, which carries the punches, is slidable upon a plurality of spaced parallel vertical guide rods 4 extending upwardly from the base plate 2. Carriage 3 is secured to and moved vertically by the ram 5 which may be operated in any approved and well-known manner. The vertical stroke of the carriage 3 is adapted to move the punches down into the mating die openings and then again elevate these punches to substantially the position shown in Fig. 1, at each stroke of the press.

The carriage 3 and base plate 2 support bers wh1ch are adapted to'operate, substantiall simultaneously on each stroke of the mac ine, on four adjacent sections or areas of the continuous metal strip 6, asshown in Fig.6. The lengths of these respective areas of the strip have been indicated by dotted lines and designated respectivelm, b, a, and d, and the same symbols have 11 used to designate the correspondin areas of the punch and die members in 2, 3 and 4. A plate 7, secured to the ower face ofca-rriage 3 by screws or bolts 8 within the section or area a, carries a plurality of down- I wardly projecting cylindrical punches 9 and 10. The punches 9 are so arranged as to 11 in the ends 13 (see Fig. 7 whereas the punches '10 are positioned to form the holes14 in the ends of each straight lamination 15 (see Flg. 8).

The plate 16, secured to the lower of carriage 3 by bolts or screws 17, carries two downwardly projecting rectangular punches 18 arranged parallel with one another, and

extending transversely of the path of movement of the metal strip 6. These punches 18 are adapted to cut out the two straight laminations 15, at the same time forming the spaces 19 between the end legs 20 and center legs 21 of the two E-shaped laminations. The punches 18 operate on section Z) of the strip 6 while punches 9 and 10 are operating on the section a of strip 6.

A pair of rectangular block punches 22 and 23, positioned to operate on sections 0 and d, respectively, of strip 6, are secured to the lower face of carriage 3, or to plate 24 thereon, by means of a pluralityof screws or similar fastening means 25. Each of these punches 22 and 23 has the same outer rectangular outline as that of one of the E shaped laminations 13. The punches 22 and 23 are positioned in staggered relation, one in advance of the other and one at each side of the longitudinal center line of the path of travel of metal strip 6.

Referring now to Fig. 4, the die-plate 26 secured to the upper face of base plate 2 is formed with a plurality of cylindrical vertical openings 27 and 28 adapted to receive the punches 9 and 10, respectively, and cooperate with these punches in cutting the holes 11 and 14 in the laminations. Plate 26 also has a pair of rectangular die openings 29 adapted to receive the punches 18 and assist in cutting out the straight laminations 15. Plate 26 also is formed to surroundthree sides of a rectangular opening 30 which receives the punch member 22. The fourth side of opening 30 is formed by one end of a block 31 secured by screws 32 to base block 2. Plate 26 also is formed to provide the cutting edges at two sides of opening 33 for punch 23, the other two sides being formed by the block 31 and a second block 34 secured to base 2 by screws 35. The blocks 31 and 34 extend above the lower plane of the path of travel of metal strip 6 so as to form stops against which the end faces 36 and 37 respectively of the strip are caused to abut between each two strokes of the. press. The openings 27, 28, 29, 30 and 33 extend completely through the base block 2, so that the pieces of metal cut from strip 6 may fall completely through the machine and be collected or stacked, as hereinafter described.

A fixed bar or side wall 38 is secured at one side of die plate 26, and the inner edge 39 of this member 38 serves as a guide for one edge of the metal strip 6. Parallel with the bar 38 and at the other side of die plate 26 is secured a bar or plate 40, and an inner movable guide member 41 adapted to bear against the other edge of metal strip 6 is carried by a plurality of pins 42 guided through horizontal passages in the bar 40 and screwed at their inner ends into the guide plate 41. The outer ends of pins 42 are provided with handles 43 so that they can be screwed into or out of plate 41 to adjust the position of this guide relative to the fixed guide 39. A- coiled compression spring 44 surrounds each pin 42 and is confined between the movable guide 41 and the fixed bar 40 so as to yieldably hold guide'41 in its normal position against the edge of metal strip 6. Guide 41 can, however, yield outwardly against the force of springs 44 to permit the passage of metal strip 6, even though there may be slight inequalities in the width thereof. The inner end of guide bar 41 is beveled, as shown at 45, to facilitate the positioning of metal strip 6 between the two guides.

A cover or stripper plate 46 bridges the die plate and is secured to the side bars 38 and 4G by bolts or screws 47. Cover plate 46 is providedv with a plurality of openings 48 which are slightly larger than the die openings 27, 28 and 29 in the plate 26, and

adapted to align vertically therewith to permit the free passage of the punch members. Cover plate 46 is also cut away, as indicated at 49 and 50, to permit the passage therethrough of the rectangular punches 22 and 23, and also to permit the die blocks 31 and 34 to project upwardly across the path of travel of the metal strip.

It should-now be apparent that the metal strip 6 is guided for longitudinal travel from right to left between the side guides 39 and 41, and between the cover plate 46 and the upper surface of die-plate 26. Between each two strokes of the press, after i the punch members have been elevated to the position shown in Fig. 1, strip 6 may be moved to the left between these guide members, until the surfaces 36 and 37 at the left hand end of the strip abut respectively against the blocks 31 and 34. As. will be hereinafter apparent, a pair of quite narrow waste strips 51 remain, one at each side of the strip, these waste strips passing at either side of the fixed blocks 31 and 34. These waste strips 51 may conveniently be utilized for pulling the strip 6 through the machine. In the example here shown, this strip-advancing operation is performed by hand, but it will be obvious that mechanical means might bo providcd for advancing the strip stcp-by-step between each two strokes of the press.

At each downard movement of the carriage 3, four separate and distinct stamping or cutting operations are performed upon four adjacent sections a, b, c and (Z of the metal strip 6. The punches 9, 10, 18, 22 and 23 are made of slightly varying lengths (see Fig. 1) so that the cutting strain will be distributed through the downward stroke of the press, but all of these punching operations take place during the same downill) 7 of the machine or by pulling on the edge waste strips 51 at the left of the machine. The operations that take place on the next downward stroke of the press,will now be described. The space a is now occupied by a blank section of strip 6 that has been advanced from the right. The punches 9 and 10 and the cooperating cutting openings 27 and 28 in die plate 26 will now cut out the holes 11 and 14. Section 6, before this stroke of the press, is occupied by a portion of strip 6, in which the holes 11 and I l have been punched by the preceding stroke of the press. The downward movement of punches 18 will cut out the two straight laminations 15, these laminations falling down through a chute 52 and *being collected in a receptacle 52*. Before this stroke, section a is occupied by a portion of strip 6, such as indicated in section b of Fig. 6. In other words, the corner holes 11 and the laterally extending slots 19 have been cut by the two preceding strokes of the press. The downward stroke of punch 22 will now cut out one of the E-shaped laminations from substantially one-half of the.

metal strip occupying the area a. It will be noted that this punch 22 cuts three sides of the lamination, the other side 36 having been cut by the preceding stroke of the press. Before this stroke, which we are now considering, the section (1 is occupied by the half end portion of the strip indicated in section 0 in Fig. 6. The downward stroke of punch 23 cuts the other E-shaped lamination 13 from this end portion of the-strip. This punch 23- cuts two sidesof this lamination, the other two sides having been cut during the preceding stroke by the two punches 22 and 23, V respectively.

It will be apparent that although the cutting of the laminations v progresses through four succeeding strokes of the press,

two laminations of each type are completed at each stroke. Each of these laminations is cut completely on all sides thereof, so that the width of metal strip 6 is not relied upon for the accuracy of any of. the dimensions and the laminations will be of absolutely a" uniform-size and shape. All ofthe material of strip 6 is utilized except for the very narrow edge strips 51, these edge waste strips being necessary in order that the laminations may be cut accurately on all sides. As

hereinabove pointed out, the waste strips 51- are also utilized for advancing the metal strip throughthe machine.

The E-shaped laminations 13 as they are cut may be collected in stackers 54 which need not he described, as the present invention is concerned exclusively with the method tinuously cut from a single metal strip, even though this strip is not of absolutely accurate width. There is practically no metal waste, except for the narrow edge strips which allow for possible inaccuracies in the width of the original stock strip, or in the positioning of the strip within the machine.

The apparatus disclosed herein is claimed in my (to-pending application, Serial No. 363,754, filed May 17, 1929. a

I claim:

1. Method of making core laminations from a long, relatively narrow strip which consists in cutting successive pairs of oblong openings transversely of'and entirely within the strip and severing the strip longitudinally thereof across said openings and also transversely thereof between each pair of openings to form- E-shaped bodies.

2. Method of making core laminations from av long, relatively narrow strip which consists in cutting successive pairs 0 oblong openings transversely of and entirely within the stripjand severing the strip longitudinally thereof across said openings and along the edges of the strip'and also transversely thereof between each pairj-o'fvopenings to form E-shaped bodies. v

3. Method of making core laminations from a long, relatively narrow stri which consists in cutting successive pairs 0 oblong openings transversely of and entirely within the strip, and then, b successive operations, cutting ofi E-shaped 'es alternately from one side and the other of the 'stri 4. Method of making core aminations from a long, relatively narrow stri which consists in cutting successivepair-sol oblong .opemngs transversely of and entirely within -nal edges of. the strip, and bya succession of transverse cutsextending to the central longitudinal cuts severing E-shaped bodies alternately'froin oneside and the other of the strip. Y p 1 5. Method of making successive sets of oblong and E-shaped core laminations from a long, relatively narrow strip which consists in punching perforations in the strip spaced to extend-through the laminations to be cut from the strip; then cutting two oblong bodies from the strip to form spaced openings extending transversely of the strip and Within the edges'thereof; and thereafter, by successive operations, severing E-shaped bodies alternately from opposite sides of the stri Y 6. lvlethod of making successive sets of oblong and E-shapcd core laininations from a long, relatively narrow strip which consists in punching peritorationsvin the strip spaced to extend through the laminetions to be cut from the strip; then cutting succesmreme sive pairs of oblong bodies from the strip to form spaced openings extending transversely of the strip and Within the edges thereof; and thereafter, by a succession of longitudinal cuts made at the center of the strip across the oblong openings and along the longitudinal edges of the strip, and by a succession of transverse cuts extending to the central longitudinal cuts severing E- shaped bodies alternately from opposite sides of the strip.

HARRY W. NORDENDALE. 

